My answer was in general to engine additives. I believe Marvel is an additive. It was brought up that it may be a scam. I don't know if it is or not but I have used additives in the past with good results. I have added STP in engines where there is some bearing noise and it did well. I have added Risilone to engines with noisy lifters and leaking seals. It hase done well also. I think most additives are fine and probably the Marvel is fine also. Maybe theres a consumer report on Marvel?